1. 17.4 Generating Electricity
Chapter 17
17.4 Generating Electricity

2. Generating Electricity
Lots of heat energy is generated from coal, gas, and oil
Most of the heat energy is “lost” as unusable energy

3. Generating Electricity
Nonrenewable resources: not replaced as it is used (ex: coal, oil, natural gas)
Renewable resources: a natural resource that can be replaced (ex: falling water, Sun, wind)

4. Electricity from Fossil Fuels
Three major fossil fuels: coal, oil, natural gas
wikipedia: fossil fuels
Because it takes so long for these resources to form, someday we will not have enough fossil fuels to produce the electricity we need.

5. Electricity from Nuclear Energy
Nuclear energy does not pollute the air like fossil fuel power plants do.

6. Electricity from Nuclear Energy
Storage of nuclear waste has always been a major disadvantage of nuclear power plants.
Uranium fuel from the reactor stays dangerously radioactive for a long time.

7. Renewable: Wind Energy
wikipedia
California was the first U.S. state to build large wind farms.
Wind farms can disturb natural habitats, and can perhaps scar a large area of scenery.

8. Renewable: Solar Energy
The Sun’s energy is often called solar energy.
A solar cell (also known as a photovoltaic cell) can convert solar energy to electricity.

9. Renewable: Hydroelectric Power
Hoover Dam
A hydroelectric (or hydropower) plant uses energy from falling water to generate electricity.

10. Renewable: Geothermal Energy
Geothermal power plants use Earth’s internal heat energy, in the form of water or steam, to produce electricity.
A geothermal heat pump system takes advantage of the relatively constant temperature of Earth’s shallow ground.

11. Renewable: Biomass Energy
Biomass is organic material from plants or animals.
In waste-to-energy plants, renewable solid waste is burned to produce electricity, which also creates some air pollution.

12. Quick Check! List 3 fossil fuels.
Are fossil fuels nonrenewable or renewable? EXPLAIN.
List 3 renewable resources.

13. Power = current x voltage
Electrical Power
Electrical power: the rate at which electrical energy is changed into other forms of energy such as heat, sound, or light.
Electrical power is measured in watts, just like mechanical power.
Power = current x voltage
P = I V

14. # of kilowatt-hours = # of kilowatts x hours
Electrical Power
Utility companies charge customers for the number of kilowatt-hours (kWh) used each month.
A kilowatt-hour is a unit of energy, not power
# of kilowatt-hours = # of kilowatts x hours

15. Electrical Power Example
a. A toaster uses 12 amps of current when plugged into a 120 volt outlet. What is the power rating of the toaster in watts?
b. What is the power rating in kilowatts?
c. How many kilowatt-hours does the toaster use if you use it for 2.5 hours a month?
d. The utility company charges $0.15 per kilowatt-hour. What does it cost you to use the toaster for that month?